The invention relates to a coupling device of a switchable cam follower of a valve train of an internal combustion engine, wherein this cam follower has an outer lever with an inner lever running between its arms and also, on its bottom side, a single-end contact for a gas-exchange valve, wherein, on this end, the levers move on an axis in a pivoting motion relative to each other, wherein a dome-shaped contact for a support element is inherent in the outer lever on a crosspiece on the other end and at least one of the levers has a cam run-on surface, wherein the coupling device in the outer lever consists of a borehole above the contact, wherein, for a coupled case [large valve stroke], the coupling slide can be brought into contact using a hydraulic medium that can be guided section by section into a pressure space from the contact before its outer end with a sub-region extending close to its inner end with a catch surface of an adjacent cross area of the inner lever, and wherein, for a decoupled case [small or 0 valve stroke], the coupling slide is displaced out of contact from the catch surface for a disconnected/reduced hydraulic medium pressure via the force of a compression spring.
Such coupling devices in cam followers that can be switched off or reversed are adequately known in the technical world. Disadvantages are their relatively complicated construction and also their expensive assembly processes. It has also been determined that in a plurality of the known devices, there is the risk that at least one of the components could become loose in an undesired way during operation.